Intelligent Network Services

ABSTRACT

A method and control node ( 110 ) and computer program are disclosed for handling Intelligent Network services associated with a call to a subscriber of a mobile telecommunications network, the network comprising said control node ( 110 ), a HLR  5  ( 111 ) and one or more SCPs ( 121, 122, 123 ). Said control node ( 110 ) a) sends ( 101 ) to said HLR ( 111 ) one or more requests for routing information associated with said call; b) receives ( 102 ) from said HLR ( 111 ) service trigger elements associated with said services; c) uses said trigger elements for invoking ( 103 ) said services in said one or more SCPs ( 121, 122, 123 ); and d) receives ( 104 ) from said one or more 10 SCPs ( 121, 122, 123 ) information related to said services associated with said trigger elements.

FIELD OF INVENTION

The invention relates to a method and control node for handlingIntelligent Network services associated with a call to a subscriber of amobile telecommunications network.

BACKGROUND

Intelligent Network services are well known in the state of the arttelecommunications networks such as GSM (Global System for Mobilecommunications).

The central component of the Core Network subsystem of a GSM network isthe Mobile services Switching Center (MSC). It acts like a switchingnode of the PSTN or ISDN, and additionally provides all thefunctionality needed to handle a mobile subscriber, such asregistration, authentication, location updating, handovers, and callrouting to a roaming subscriber. These services are provided inconjunction with several functional entities, which together form theCore Network subsystem. A Gateway MSC (GMSC) provides the connection tothe fixed networks (such as the PSTN or ISDN). Signaling betweenfunctional entities in the Core Network subsystem uses Signaling SystemNumber 7 (SS7), used for trunk signaling in ISDN and widely used incurrent public networks.

The Home Location Register (HLR) and Visitor Location Register (VLR),together with the MSC, provide the call-routing and roaming capabilitiesof GSM. The HLR contains all the administrative information of eachsubscriber registered in the corresponding GSM network, along with thecurrent location of the mobile station. The location of the mobilestation is typically in the form of the signaling address of the VLRassociated with the mobile station. There is logically one HLR per GSMnetwork, although it may be implemented as a distributed database.

The VLR contains selected administrative information from the HLR,necessary for call control and provision of the subscribed services, foreach mobile station currently located in the geographical areacontrolled by the VLR and currently served by that VLR. Although eachfunctional entity can be implemented as an independent unit, currentlyall manufacturers of switching equipment implement the VLR together withthe MSC, so that the geographical area controlled by the MSC correspondsto that controlled by the VLR, thus simplifying the signaling required.The MSC contains no information about particular mobile stations; thisinformation is stored in the location registers.

Next, a typical incoming call setup (mobile terminating call) in a GSMnetwork is described.

When a subscriber places a call to a mobile phone, he dials thetelephone number associated with the phone user, the so-called MobileStation ISDN (MSISDN) number, and the call is routed to the mobile phoneoperator's Gateway MSC. A gateway is a node used to interconnect twonetworks. The gateway is often implemented in an MSC, in which case theMSC is referred to as the GMSC. The GMSC acts as the “entrance” fromexterior portions of the Public Switched Telephone Network onto theprovider's network.

As noted above, the phone is free to roam anywhere in the operator'snetwork or on the networks of roaming partners, including in othercountries. So the first job of the Gateway MSC is to determine thecurrent location of the mobile phone in order to connect the call. Itdoes this by consulting the HLR, which, as described above, knows whichVisited Location Register (VLR) the phone is associated with at themoment, if any.

When the HLR receives this query message, it determines whether the callshould be routed to another number (called a divert), or the call shouldbe routed directly to the mobile station of the called subscriber.

If the owner of the phone has previously requested that all incomingcalls be diverted to another number, which supplementary service is alsoknown as Call Forwarding Unconditional (CFU) to a Forwarded-to-Number(FTN), then this FTN is stored in the HLR. If that is the case, then theFTN is returned to the Gateway MSC for immediate routing to thatdestination.

If the mobile station is not currently associated with a VLR (e.g.because the phone has been turned off), then the HLR returns a numberknown as the Call Forwarding Not Reachable (CFNRc) number to the GMSC,and the call is forwarded there. Many operators may set this valueautomatically to the phone's voice mail number, so that callers mayleave a message.

Finally, if the HLR knows that the phone is in the jurisdiction of aparticular VLR, then it will request a temporary number, a so calledMobile Station Roaming Number (MSRN) from that VLR. This number isrelayed to the GMSC, which uses it to route the call to another MSC,called the Visited MSC (VMSC).

When the call is received by the VMSC, the MSRN is used to find thephone's record in the VLR. This record identifies the phone's locationarea. Paging occurs to all mobile phone masts in that area. When thesubscriber's mobile responds, the exact location of the mobile isreturned to the VMSC. The VMSC then forwards the call to the appropriatephone mast, and the phone rings. If the subscriber answers, a speechpath is created through the VMSC and GMSC back to the network of theperson making the call, and a normal telephone call follows.

It is also possible that the phone call is not answered. If thesubscriber is busy on another call (and call waiting is not being used),then the VMSC routes the call to a pre-determined Call Forwarding Busy(CFB) number. Similarly, if the subscriber does not answer the callafter a period of time (typically 30 seconds), then the VMSC routes thecall to a pre-determined Call Forwarding No Reply (CFNRy) number. Onceagain, the operator may decide to set this value by default to the voicemail of the mobile so that callers can leave a message.

An Intelligent Network (IN) is a network that is coupled to atelecommunications network that enables operators to deployoperator-specific Value Added Services (VAS). The intelligence thatresides in the switch is augmented by intelligence from the IntelligentNetwork, which is placed in computer nodes that are distributedthroughout the network. This provides the network operator with themeans to develop, deploy and control services more efficiently. Newservices can be rapidly introduced into the telecommunications network.Once introduced, services are easily customized to meet individualcustomers' needs.

IN services are typically provided by a Service Control Point (SCP). AnSCP is a control computer that communicates with other nodes andentities in the telecommunications network. The SCP comprises theservice logic of one or more IN services and optionally IN servicesubscription data that allows the SCP to execute an IN service inaccordance with the specific settings of a subscriber, i.e. tailor theservice execution to the subscriber. When a call is established, thetelecommunications network may query the SCP and ask for instructionsfor handling this call. For instance, an SCP is consulted to provide thetranslation of an 800 number to an actual phone number and to bill theowner of the 800 number for the call. SCPs may be physically separatedfrom other components of the Intelligent Network or may be combined withthese other components into a single node.

In a GSM network the IN service subscription information is stored inthe HLR. Two types of information reside in the HLR: (1) staticsubscriber information and (2) dynamic subscriber information. Thelatter is e.g. needed to allow incoming calls to be routed to the mobilesubscriber. The HLR stores, amongst others:

-   -   the International Mobile Subscriber Identity (IMSI); an internal        subscriber identity used only by the network;    -   MSISDN number;    -   VLR address;    -   subscriber data on supplementary services.

IN services may be divided into two categories. One category comprisesservices to be invoked for subscribers who initiate a call (MobileOriginated Call—MOC). These services are called Mobile Originating (MO)services. An example of an MO service is outgoing call screening.

Each IN service subscriber is marked in his HLR with an OriginatingCAMEL Subscription Information (O-CSI) element, which is used toidentify a specific service at the SCP. The O-CSI initiates thetriggering of the MOC service as soon as the subscriber initiates a MOcall. In the above example CAMEL is deployed, which stands for“Customised Applications for Mobile network Enhanced Logic”. CAMEL wasdeveloped as a standard for extending landline IN telephony servicessuch as call waiting and call forwarding to GSM mobile phones.

The other category comprises services to be invoked for subscribers whoreceive a call (Mobile Terminated Call—MTC). These services are calledmobile terminating (MT) services. Examples of mobile terminatingservices are call diversion services and Personal Greeting Service(PGS). PGS is a service that is associated with a roaming leg. PGSentails that when a signalling connection is established between a GMSCand VMSC (a so called “roaming leg”), then a personalised greeting isplayed to the calling party. The personalised greeting replaces theconventional alerting tone (“ring tone”). As such, the personalisedgreeting is primarily related to the establishment of the roaming leg;the ring tone becomes active only when the roaming leg is establishedand the called party is alerted. Each IN service subscriber is marked inhis HLR with a Terminating CAMEL Subscription Information (T-CSI) flag,which is used to identify a specific service at the SCP. This initiatesthe triggering of the MTC service during a call attempt to thesubscriber.

According to the state of the art, a control node may query a HLR duringMTC handling to obtain instructions from the HLR. The control node maybe a GMSC. In response to the query by the control node, the HLR maysend IN trigger information for the terminating call. The IN triggerinformation exchanged between the HLR and the control node has beenstandardized. For example T-CSI is the GSM standardized IN triggerinformation for terminating calls, as specified by 3GPP (3rd GenerationPartnership Project) in 3GPP TS 29.002. IN trigger information comprisesamong others the address of the SCP where the IN service resides and theservice key, which identifies a particular IN service within the SCP.

The control node uses the IN trigger information to invoke the INservice in the SCP as specified for the subscriber in the IN triggerinformation. In response to the service invocation, the SCP sends aninstruction to the control node to e.g. continue call set up or toterminate the call depending on the outcome of the service execution.Current networks are typically arranged to handle a single invocation ofan IN service for an MTC. Recent developments show however, that thereis a need to invoke two or more IN services during terminating callhandling.

Patent application WO00/25528 discloses a Service Interaction Manager,which is included in an SCP. The task of the Service Interaction Manageris to determine which of the available services in the SCP should beexecuted for a subscriber and to invoke those services in a particularsequence.

SUMMARY

It is an object of the invention to provide a method and devices thatovercome the drawbacks of the state of the art by permitting subscribersto have more than one IN Service for one call.

In a first aspect of the invention a method is proposed for handlingIntelligent Network services associated with a call to a subscriber of amobile telecommunications network, the network comprising a controlnode, a Home Location Register and one or more Service Control Points,the method comprising the steps of:

-   -   a. said control node sending to said Home Location Register, one        or more requests for routing information associated with said        call;    -   b. said control node receiving from said Home Location Register        service trigger elements associated with said services;    -   c. said control node using said trigger elements for invoking        said services in said one or more Service Control Points;    -   d. said control node receiving from said one or more Service        Control Points information related to said services associated        with said trigger elements.

In this way multiple service trigger elements may be handled for asubscriber who is subscribed to one or more IN services pertaining toone call of the subscriber. IN Services need not be aware of theexistence of one or more other IN services in that control node for thatcall. In other words, a first service does not need to know whether asecond service will be invoked and vice versa. Since the services do notrequire knowledge about the possible invocation of other IN services forthis call, the services may run on different platforms and may besupplied by different vendors.

There are several embodiments of the invention.

For example, the invention may provide for a Home Location Register tosend a first service trigger element of said multiple service triggerelements, in response to a first request for routing information and asecond service trigger element of said multiple service trigger elementsin response to a second request for routing information.

The first request for routing information may comprise:

-   -   MSISDN number of the subscriber.

The response to the first request for routing information may comprise:

-   -   the first service trigger element.

The second request for routing information may comprise:

-   -   MSISDN number of the subscriber;    -   an indication that the HLR shall suppress the first service        trigger element in the response. This indication may e.g. be the        “suppress T-CSI” parameter.

The response to the second request for routing information may comprise:

-   -   an MSRN to be used for the call to the served subscriber;    -   the second service trigger element;    -   a prefix or a suffix to the MSRN of the subscriber.

The MAP message may be sent from the HLR to a GMSC in multipleSignalling Connection Control Part messages, due to MAP segmentation. Afirst service, for example a pre-paid charging service, is executed in afirst service control point and a second service, for example PGS, isexecuted in a second SCP.

In this way the pre-paid service and PGS may be offered to the samesubscriber; the pre-paid service and PGS may run on different platformsand are not related to one another.

When the present invention is used for PGS, the calling subscriber mayhear any call progress message even when early call forwarding or latecall forwarding with optimal routing takes place.

Another advantage of the invention is, that PGS may be offered toVirtual Private Network (VPN) subscribers.

In a second aspect of the invention a control node is proposed forhandling Intelligent Network services associated with a call to asubscriber of a mobile telecommunications network, the networkcomprising said control node, an HLR and one or more SCPs; the controlnode configured to send to said HLR one or more requests for routinginformation associated with said call; the control node furtherconfigured to receive from said HLR multiple service trigger elementsassociated with said services, and for invoking said services in saidone or more SCPs by using said trigger elements; the control nodefurther configured to receive from said one or more SCPs informationrelated to said services associated with said trigger elements.

In a preferred embodiment the control node comprises a GMSC. The controlnode may however also comprise a device such as an MSC or an SCP.

A third aspect of the invention proposes a computer program, comprisingprogram instructions for causing a computer to perform the methodaccording to the invention.

The computer program may be stored on a carrier and may comprisecomputer executable instructions for causing a computer to perform themethod according to invention.

The carrier of the computer program may be a record medium, computermemory, read-only memory or an electrical carrier signal.

The present invention proposes that multiple IN services may be providedfor a particular call type to a subscriber. Hereto, an HLR may haveregistered multiple indications of particular IN call type subscriptions(hereinafter referred to as IN trigger elements).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a prior art configuration of devices in amobile telecommunications network.

FIG. 2 is a signalling diagram of the method and devices according tothe present invention.

FIG. 3 is a block diagram of devices according to the present invention.

FIG. 4 is a signalling diagram of an embodiment of the method of thepresent invention.

FIG. 5 is a signalling diagram of an embodiment of the method of thepresent invention.

FIG. 6 is a signalling diagram of an embodiment of the method of thepresent invention.

DETAILED DESCRIPTION

For the purpose of the present invention, MT call handling in the GMSCmay be divided in two logical parts:

(1) Terminating call handling;(2) Roaming leg handling.

The terminating call handling includes the retrieving of T-CSI from theHLR and the invocation of the first CAMEL service. The first CAMELservice may enforce call restriction or may apply call forwarding.Typically, this first CAMEL service is also used for terminatingcharging, for the case that the called subscriber is roaming. The HLRmay also return other IN trigger elements in combination with T-CSI.

The roaming leg handling includes the retrieving of the MSRN from HLRand the routing of the call from the GMSC to the terminating MSC, wherethe called party is registered at that moment. It is noticed that“roaming leg” is equally applicable for the case that the subscriber isin the Visited Public Land Mobile Network (VPLMN) and for the case thatthe subscriber is in the Home Public Land Mobile Network (HPLMN). i.e.“roaming” shall in this case not be associated with “being in anothernetwork or in another country”.

The present invention proposes that the invocation of two IN servicesfor an MT call is done along the line of above-described distinction.According to the present invention, two types of IN services for MT callmay be defined:

(1) IN services that need control over the MT call and that may need thecapability to influence the routing of the call. These kind of INservices also need to know the location of the destination subscriber,so charging may be applied.(2) IN services that are required only for the roaming leg to thedestination subscriber. This type of IN service is invoked only when aroaming leg is established, i.e. the GMSC has received an MSRN from theHLR.

If the HLR returns a Forwarded-to-Number (FTN) instead of an MSRN, thenthere will not be a roaming leg and consequently, no roamingleg-associated IN service will be invoked.

FIG. 1 is a block diagram of a prior art configuration of devices in amobile telecommunications network. The shown entities belong, at leastconceptually, to an intelligent network that is distinct from the mobilecommunications network. The intelligent network includes HLR 111, SCP1121, SCP2 122 and GMSC110. GMSC 110 interfaces to SCP1 and SCP2 as wellas to HLR 111 for performing well known IN triggering functions. SCP1and SCP2 contain intelligent network services that may be invokedsequentially during the handling of a mobile terminating call.

FIG. 2 is a signalling diagram of the method and devices according tothe present invention with a general overview of relations betweenvarious elements. The method comprises next steps:

-   Step 101 A control node 110 sends to a HLR 111, one or more requests    for routing information associated with said call;-   Step 102 The HLR 111 sends to said control 110 node multiple service    trigger elements associated with said services;-   Step 103 The control node 110 uses said trigger elements to invoke    one or more services in one or more Service Control Points 121, 122,    123;-   Step 104 The one or more Service Control Points 121, 122, 123 sends    to said control node 110 information related to on one or more    services associated with said trigger elements.

FIG. 3 is a block diagram of devices and their interrelations accordingto the present invention.

The lines between the blocks (devices) represent communication paths.HLR 111 may communicate with GMSC 110 and to VMSC 112. GMSC maycommunicate with SCP1 121 and other subsequently invoked SCPs (SCPn)122. GMSC 110 may communicate with VMSC 112.

FIG. 4 is a signalling diagram of an embodiment of the method of thepresent invention comprising a communication sequence between thedevices as shown in FIG. 3, comprising GMSC 110, HLR 111, multiple SCPs121, 122 and a VMSC 112. In this example a subscriber is subscribed to aCAMEL service and additionally to at least one service, which may be anIN, service. For this example only the communication with two SCPs 121,122 is shown. However, steps 6-11 may be repeated for a third SCP and soon. The following steps occur:

-   Step 401 ISUP Initial Address Message (IAM) arrives at the GMSC 110;    the GMSC 110 analyses the Called Party Number in ISUP IAM and    deduces that the Called Party Number is an MSISDN belonging to its    own network.-   Step 402 The GMSC 110 sends MAP Send Routing Information (SRI) to    the HLR 111. The GMSC 110 indicates in MAP SRI that it supports    CAMEL.-   Step 403 The called subscriber has a subscription to a CAMEL service    for MT call handling. As a result, the HLR 111 sends MAP SRI-Res to    the GMSC 110, including the IN trigger information for MT calls,    T-CSI.-   Step 404 The GMSC 110 uses T-CSI to invoke a CAMEL service. The GMSC    110 instantiates an internal GSM Service Switching Function (gsmSSF)    entity; the gsmSSF sends CAP Initial Detection Point (IDP) to the    SCP. The address of the SCP1 121, and other data related to this IN    dialogue, is obtained from T-CSI. The gsmSSF function interworks    with the GMSC. Based on information defined in the user's    subscription, and sent from the HLR to the GMSC, service triggers    within the GMSC and gsmSSF are set. These triggers are used to    dictate when the gsmSSF shall communicate with the gsmSCF. This in    turn will determine how IN based services are handled.-   Step 405 The SCP1 121 responds with CAP Continue (CUE), to inform    the GMSC 110 that MT call handling may continue, i.e. the call may    be delivered to the called subscriber. The control dialogue between    SCP1 121 and GMSC 110 may be retained. The CAMEL service in SCP1 121    does not need to have knowledge about other IN services than the    CAMEL service it's currently executing.-   Step 406 The GMSC 110 sends a second interrogation to the HLR 111,    i.e. sends a second MAP SRI to the HLR 111. The second MAP SRI    includes the flag “suppress T-CSI”.-   Step 407 The HLR 111 recognizes the MAP SRI as a second SRI, by    virtue of the presence of “suppress T-CSI”, and responds by sending    MAP Provide Roaming Number (PRN) to the VMSC 112 where the called    party is currently registered.-   Step 408 The VMSC 112 allocates an MSRN for this call and returns    the MSRN to the HLR 111, by sending MAP PRN-Res to the HLR 111.-   Step 409 The HLR 111 forwards the MSRN to the GMSC 110, by sending    MAP SRI Response (SRI-Res) to the GMSC 110. The called subscriber    subscribes to a second IN service for MT call handling. The second    IN service is of the type Roaming Leg handling, as described in an    earlier part of the present invention disclosure. The HLR 111    includes the IN trigger information associated with this second IN    service, in the MAP SRI-Res. For the purpose of the present    invention, this second IN trigger information is named “RICK”    (Roaming leg IN Category Key). RICK may have the structure as T-CSI    or TICK (Terminating IN Category Key). In order to be able to    receive RICK, the GMSC 110 would have indicated in the 2nd MAP SRI    (step 6) that it supports this information element, i.e. it supports    RICK. This indication of “RICK support” is similar to the indication    of “TICK support”. The “TICK support”, which is sent from GMSC to    HLR, indicates to HLR that it supports the TICK. The TICK has    functionality that may be compared with T-CSI; TICK is, however, not    standardised.-   Step 410 The GMSC 110 recognizes that the MSRN is accompanied by a    RICK. The RICK serves as an indication for the GMSC 110 that the    roaming leg shall be subject to an IN service. The GMSC 110    therefore uses RICK to invoke an IN service, by sending CAP IDP to    the SCPn 122. The address of the SCPn 122, and other data related to    this IN dialogue, is obtained from RICK.-   Step 411 The SCPn 122 responds with CAP CUE, to inform the GMSC 110    that MT call handling may continue, i.e. the roaming leg towards the    called subscriber may be established.-   Step 412 The GMSC 110 establishes the roaming leg towards the called    subscriber, by sending ISUP IAM towards the destination exchange.    The ISUP IAM contains the MSRN that was received from the HLR 111.-   Steps 401-408 represent normal GSM call handling.-   Step 409 represents an enhancement to the existing MT call handling.    The HLR 111 will normally return only the MSRN to the GMSC 110. Step    409 adds the RICK to the MAP SRI-Res.-   Step 410 and step 411 do not exist in existing Roaming Leg handling.    These steps represent the invocation of the second IN service for    the MT call handling in the GMSC 110.

When the call is delivered to the called subscriber, the two IN servicesmay remain active. The first IN service, triggered as a result of thesending of T-CSI to the GMSC 110, may remain active for the entire calland has the full capability available as allowed by the IN protocol usedfor that service.

The second IN service, triggered as a result of the sending of RICK tothe GMSC 110, may also remain active for the entire call. This INservice shall, however, use the IN capability with certain restrictions.As an example, this service shall not apply call forwarding, as thatwould affect a pre-paid service for the call.

The present invention may be applied on various types of GSM callforwarding. This may be shown most adequately by taking a service likePersonal Greeting Service (PGS) as an example. In the case of callforwarding, the destination of the call changes. Some operators requirethat the PGS service be terminated when call forwarding to a voicemailbox takes place.

With regard to terminating a PGS service in a call forwarding situationthere are basically two types of call forwarding: Early call forwarding(ECF) and Late Call Forwarding (LCF) When early call forwarding takesplace in the GMSC 110, the GMSC 110 does not receive an MSRN form theHLR 111 for this call and no roaming leg is established. The GMSC 110will not establish a roaming leg to the called party and as a result, noroaming-leg IN service will be invoked.

In the case of early call forwarding, the HLR 111 does not return anMSRN in the second SRI Result and, according to the present invention,does not return the RICK. The GMSC 110 now forwards the call to theforwarded-to destination, which may e.g. be a voice mailbox or callcompletion service. Since the HLR 111 has not returned RICK, there willnot be a PGS invocation. The calling subscriber may now hear anyannouncement that is played by the voice mailbox, even when the voicemailbox defers the generation of the ISUP Answer Message (ISUP ANM) fora defined duration.

When late call forwarding takes place in the VMSC 112, then OptimalRouting of Late Call Forwarding (ORLCF) may be applied to return thecall handling to the GMSC 110. The GMSC 110 terminates the roaming legand hence, the roaming-leg IN service will be terminated as well. In thecase of late call forwarding, the call is already routed to thedestination MSC of the called subscriber. When the late call forwardingcondition occurs, the VMSC 112 may send MAP Resume Call Handling (RCH)to the GMSC 110; the sending of MAP RCH is part of ORLCF.

When the GMSC 110 receives MAP RCH and approves the request for ORLCF,it releases the roaming leg and creates a forwarded leg. The callingparty may hear any announcement generated by the forwarded-todestination.

Some operators deploy a voice mailbox system whereby the initialannouncement is free of charge. This may be accomplished by having thevoice mailbox defer the generation of the ISUP ANM. If PGS remainsactive in such situation, then the calling party will not hear anyannouncement that is played between ISUP Address Complete Message (ACM)and ISUP ANM. Reason is that the personal greeting remains active untilthe ISUP ANM is detected. The initial announcement of the voice mailwould in that case not be heard.

The present invention resolves that problem, since PGS will beterminated in the case of late call forwarding in combination withORLCF.

If late call forwarding is not subject to ORLCF, then the Roaming Legservice may monitor for ISUP messages such as Call Progress (CPG) andACM. These ISUP messages may indicate that forwarding is taking place.

Some operators apply a service node solution for PGS. This means thatfor PGS subscribers, the roaming leg needs to be routed through aspecial service node (located in-line with the ISUP traffic link for theroaming leg). The service node will propagate the call to thedestination MSC. The routing of the roaming leg through a service nodemay be accomplished in accordance with the present invention. The INservice that is invoked with RICK may provide a prefix for the MSRN,resulting in that the call is routed through the service node.

Alternatively, the RICK that is included in the SRI-Res may have theform of a number prefix; a switching node such as a GMSC places the RICKin front of the MSRN, prior to forwarding the call to a next switchingnode.

The B-number analysis in this transition node may be configured suchthat the RICK results in the selection of a route to the service node.

The concept of a subscribed or generic IN service for a roaming leg maybe used for the following type of services:

-   -   Personal greeting: the playing of the personal greeting is        required only when the roaming leg is successfully established;        if the roaming leg can, for whatever reason, not be established        or is terminated before answer, then the personal greeting is        not required. An operator may wish to invoke PGS prior to the        allocation of a MSRN for the call. The effect of that may be        that when forwarding to a second called party takes place, the        calling party will still hear a first party's personalised        greeting. In addition, such configuration would have the effect        that call forwarding announcements may not be heard.    -   Service-node routing: for a particular subscriber, the roaming        leg may need to be routed through a service node.    -   Carrier selection: a subscriber may subscribe to a carrier        selection service that is applicable for roaming leg only.

When the HLR 111 sends SRI-Res to GMSC 110 including MSRN, it mayinclude RICK. As an implementation option, the HLR 111 may applycriteria for the inclusion of RICK in SRI-Res, similar to the casewhereby the HLR 111 applies criteria for the inclusion of T-CSI in thefirst SRI-Res. These criteria may e.g. be:

-   -   include RICK in SRI-Res only when subscriber is in HPLMN;    -   include RICK in SRI-Res only when the incoming call is a speech        call

Not all MT calls need a terminating IN service. Likewise, not all MTcalls need a RICK service. As an example, when a pre-paid subscriber isin the HPLMN, the HLR 111 may suppress T-CSI in SRI. As a result, therewill not be a MT call service triggered. If the invocation of theRoaming leg service is still required in this case, then the HLR 111 mayinclude RICK in the first SRI-Res. The further handling of RICK in theGMSC 110 is as described earlier.

FIG. 5 is a signalling diagram of an embodiment of the method of thepresent invention, wherein the invocation of multiple services isperformed by a GMSC 110 interrogating an HLR 111 for multiple (IN)services before the GMSC 110 sets up the roaming leg. In this embodimentthe HLR 111 sends all the information of the IN services at the firstinterrogation. Steps 501-502 are performed according to the currentstate of the art. In this example 3 SCPs are involved, although theinvention is applicable to multiple SCPs.

-   Step 501 ISUP IAM arrives at the GMSC 110.-   Step 502 The GMSC 110 analyses the Called Party Number in ISUP IAM    and deduces that the Called Party Number is an MSISDN belonging to    its own network. The GMSC 110 sends MAP SRI to the HLR 111. The GMSC    110 indicates in MAP SRI that it supports CAMEL. The GMSC may    support multiple CAMEL phases.-   Step 503 The called subscriber has a subscription to a CAMEL service    for MT call handling. As a result, the HLR 111 sends MAP SRI-Res to    the GMSC 110 including IN trigger information for MT calls, T-CSI.-   Step 504 The GMSC 110 uses T-CSI to invoke a CAMEL service. The GMSC    110 instantiates an internal gsmSSF entity; the gsmSSF sends CAP IDP    to the SCP 121. The address of the SCP1 121, and other data related    to this IN dialogue, is obtained from T-CSI.-   Step 505 The SCP1 121 responds with CAP Continue (CUE) or CAP    Connect (CON), to inform the GMSC 110 that MT call handling may    continue, i.e. the call may be delivered to the called subscriber.    The control dialogue between SCP1 121 and GMSC 110 may be retained    or terminated, depending on IN service requirements. The CAMEL    service in SCP1 121 has no knowledge about other IN services than    the CAMEL service that it is currently executing.-   Step 506 The GMSC 110 responds by invoking a second IN service,    which could again be a CAMEL service, based on T-CSI. The address of    SCPn 122 is obtained from the second T-CSI.-   Step 507 The SCP responds with CAP CUE or CAP CON, to inform the    GMSC 110 that call handling may continue, i.e. the call may be    delivered to the called subscriber. Here as well, the CAMEL service    in SCP2 122 has no knowledge about the first service and the third    service for this call.-   Step 508 The GMSC 110 checks whether further IN services are    provisioned for the subscriber; if they are, then it responds by    invoking the third IN service, which could again be a CAMEL service,    based on T-CSI. The address of SCP3 123 is obtained from the third    T-CSI.-   Step 509 The SCP 123 responds with CAP CUE or CAP CON, to inform the    GMSC 110 that call handling may continue, i.e. the call may be    delivered to the called subscriber. The CAMEL service in SCP3 123    has no knowledge about the first service and the second service for    this call.-   Step 510 The GMSC 110 checks whether further IN services are    provisioned for the subscriber; if there are no more IN services for    the subscriber, then the GMSC 110 responds by sending a second    interrogation to the HLR 111, i.e. sends a second MAP SRI to the HLR    111.-   Step 511 The HLR 111 recognises the MAP SRI as a second SRI and    responds by sending MAP Provide Roaming Number (PRN) to the VMSC 112    where the called party is currently registered.-   Step 512 The VMSC 112 allocates an MSRN and returns the MSRN to the    HLR 111, by sending MAP PRN-Res to the HLR 111.-   Step 513 The HLR 111 forwards the MSRN to the GMSC 110, by sending    MAP SRI-Res to the GMSC 110.-   Step 514 The GMSC 110 establishes the roaming leg towards the called    subscriber, by sending ISUP IAM towards the destination exchange.    The ISUP IAM contains the MSRN that was received from the HLR 111.

FIG. 6 is a signalling diagram of an embodiment of the method of thepresent invention, whereby multiple IN services are invoked for an MOcall. The following steps occur in this embodiment.

-   Step 601 A subscriber 621 registers with an MSC 623 in a visited GSM    network.-   Step 602 The MSC 623 contacts the HLR 111 in the Home PLMN of the    subscriber 621.-   Step 603 HLR 111 sends multiple trigger elements for IN services to    the MSC 623. These trigger elements are associated to IN services    for mobile originating calls and mobile forwarding calls.-   Step 604 The subscriber 621 establishes an MO call.-   Step 605 The MSC 623 uses a first trigger element to invoke a first    IN service in SCP1 121 associated with the first trigger element.-   Step 606 The first IN service in SCP1 121 gives control of the call    back to the MSC 623, by sending a CAP Continue message or a CAP    Connect message-   Step 607 The MSC 623 uses the second trigger element from the list    of trigger elements to invoke a second IN service in SCP2 122.

The steps 605 and 606 are repeated with SCP 2 122 (steps 607, 608) andSCP3 123 (609, 610) and further, until all indicated IN services areinvoked. Call processing in MSC 623 continues with step 611 as normal:

-   Step 611 The MSC 623 routes the call to the destination 627. Any of    the invoked IN services may remain active for the entire duration of    the call, or may terminate at an earlier stage.

The following scenarios are covered by the invention:

-   -   1) IN service invocation in GMSC for MT call handling, followed        by IN service invocation in GMSC for roaming leg.    -   2) IN service invocation in GMSC for roaming leg.    -   3) As (1), whereby the HLR sends multiple IN service trigger        elements in the first interrogation response, with the purpose        that these multiple trigger elements are used for the invocation        of multiple IN services associated with the MT call.    -   4) As (1), whereby the HLR sends multiple IN service trigger        elements in the second interrogation response, with the purpose        that these multiple trigger elements are used for the invocation        of multiple IN services associated with the roaming leg.    -   5) As (2), whereby the HLR sends multiple IN service trigger        elements in the second interrogation response, with the purpose        that these multiple trigger elements are used for the invocation        of multiple IN services associated with the roaming leg.    -   6) As (1), whereby (3) and (4) are combined.    -   7) As (1), whereby the HLR sends multiple IN service trigger        elements in the first interrogation response, with the purpose        that some of these multiple trigger elements are used for the        invocation of multiple IN services associated with the MT call        and some of these multiple trigger elements are used for the        invocation of multiple IN services associated with the roaming        leg.    -   8) Certain IN services for MT calls are required only when a        roaming leg is established. The present invention offers the        tools to accomplish this.    -   9) The present invention may be used to route a roaming leg        through an ISUP service node on a subscription basis or        generically for all served subscribers.

1. A method for handling Intelligent Network (IN) services associatedwith a call to a subscriber of a mobile telecommunications network, thenetwork comprising a control node, a Home Location Register and one ormore Service Control Points, the method comprising the steps of: saidcontrol node sending to said Home Location Register, one or morerequests for routing information associated with said call; said controlnode receiving from said Home Location Register service trigger elementsassociated with said IN services; said control node using said triggerelements for invoking said IN services in said one or more ServiceControl Points; and said control node receiving from said one or moreService Control Points information related to said IN servicesassociated with said trigger elements.
 2. The method according to claim1, wherein said Home Location Register sends a first service triggerelement of said multiple service trigger elements in response to a firstrequest for routing information and a second service trigger element ofsaid multiple service trigger elements in response to a second requestfor routing information.
 3. The method according to claim 1, whereinsaid Home Location Register sends said multiple service trigger elementsin response to a first request for routing information.
 4. The methodaccording to claim 2, wherein said Home Location Register sends therequested routing information in response to a second request forrouting information.
 5. The method according to claim 2, wherein saidsecond request for routing information is associated with theestablishment of a signaling connection between said control node and aVisited Mobile services Switching Center.
 6. The method according toclaim 1, wherein said requested routing information comprises a MobileStation Roaming Number to be used for the call to said subscriber. 7.The method according to claim 1, wherein a plurality of said servicetrigger elements is comprised in one Mobile Application Part message. 8.The method according to claim 7, wherein said one Mobile ApplicationPart message is sent from said Home Location Register to said ControlNode in multiple Signaling Connection Control Part messages, due toMobile Application Part segmentation.
 9. The method according to claim1, wherein one or more of said service trigger elements is included in aMobile Station Roaming Number as a prefix or a suffix.
 10. The methodaccording to claim 1, wherein said service trigger elements compriseseparate parameters.
 11. The method according to claim 1, wherein afirst service of said IN services is executed in a first Service ControlPoint of said one or more Service Control Points and a second service ofsaid IN services is executed in a second Service Control Point of saidone or more Service Control Points.
 12. The method according to claim11, wherein a first IN service of said services is a pre-paid chargingservice.
 13. The method according to claim 11, wherein a second serviceof said IN services is a mobile terminating service such as a personalgreeting service.
 14. The method according to claim 1, wherein saidcontrol node is a Gateway Mobile Switching Centre.
 15. The methodaccording to claim 2, wherein said first request contains a MobileStation ISDN number of said subscriber.
 16. The method according toclaim 2, wherein said second request contains a Mobile Station ISDNnumber of said subscriber and a “Suppress T-CSI” parameter.
 17. Themethod according to claim 1, wherein a first or a second request of saidone or more requests for routing information comprises a MobileApplication Part Send Routing Information message.
 18. A control nodefor handling Intelligent Network services associated with a call to asubscriber of a mobile telecommunications network, the networkcomprising said control node, a Home Location Register and one or moreService Control Points; the control node comprising: means for sendingto said Home Location Register one or more requests for routinginformation associated with said call; means for receiving from saidHome Location Register multiple service trigger elements associated withsaid services, and for invoking said services in said one or moreService Control Points by using said trigger elements; and means forreceiving from said one or more Service Control Points informationrelated to said services associated with said trigger elements. 19.-21.(canceled)